Uvavanyo lwaselabhoratri lokuxilongwa kwe-COVID-19 olusebenzayo ngoku njengoko kucetyiswe ngamaqumrhu eengcaphephe zehlabathi luyaphononongwa kwaye luvavanywe.
I-COVID-19 isifo, eyavela eWuhan China, iye yachaphazela amazwe angaphezu kwama-208 ukuza kuthi ga ngoku. Uluntu lwezenzululwazi kwihlabathi lonke lubekwe ngomngeni obalulekileyo kwiinyanga ezimbalwa ezidlulileyo, ukuphuhlisa iimvavanyo zokuxilonga kuba Covid-19 ukufunyaniswa kwezifo ukuze kuhlolwe izigulana kunye nabantu abarhanelekayo ukuze kulawulwe ngempumelelo kwaye kulawuleke ubhubhane.
Phambi kokuba sivavanye iindlela zangoku kunye nezenzo ezisetyenziswayo ukubhaqa i-COVID-19, masiqale siqonde ukuba yintoni ebangela i-COVID-19 kwaye ubani uluphuhlisa njani uvavanyo lokujonga esi sifo. Isifo se-COVID-19 sibangelwa yi-RNA exineneyo intsholongwane ezo zoonotic, nto leyo ethetha ukuba banokuwela imiqobo yezilwanyana ukusuka kwizilwanyana ukuya ebantwini, kwaye kunokubangela, ebantwini, ukugula ukusuka kwingqele eqhelekileyo ukuya kwizifo ezinzima ngakumbi njenge-MERS kunye ne-SARS. Intsholongwane ebangela i-COVID-19 ngoku ibizwa ngokuba yi-SARS-CoV-2 yiKomiti yaMazwe ngaMazwe yeTaxonomy yeVirus (ICTV), njengoko ifana kakhulu naleyo yabangela ukuqhambuka kweSARS (SARS-CoVs). Uvavanyo lokufumanisa isifo se-COVID-19 lunokuphuhliswa ngeendlela ezininzi.
Eyona ndlela idumileyo nesamkelweyo ngoku kwihlabathi liphela kukuphuhlisa uvavanyo lokuxilonga olunokubona intsholongwane ye-SARS-CoV-2 ngokwayo. Oku uvavanyo isekelwe ekufumaneni i-genome yentsholongwane kwisampuli yesigulane nge-RT-real time PCR (i-reverse transcriptase-time real Polymerase Chain Reaction). Oku kubandakanya uguqulo lwentsholongwane ye-RNA kwi-DNA kusetyenziswa i-enzyme ebizwa ngokuba yi-reverse transcriptase kwaye emva koko yandise i-DNA isebenzisa isethi ethile yeeprimers kunye ne-fluorescent probe, ebophelela kummandla othile kwi-viral DNA, isebenzisa i-Taq polymerase kunye nokufumanisa uphawu lwe-fluorescent. Olu vavanyo lubizwa ngokuba zii-NAATs (i-Nucleic Acid Amplification Tests). Obu buchwephesha bunokuba luncedo kakhulu ekubhaqweni kwangoko ubukho be-nucleic acid kwisampulu yesigulana, nakwizigulana ezingenazimpawu ezingabonisi zimpawu zesifo se-COVID-19 (ingakumbi kwixesha lokufukamela leentsuku ezili-14-28) nakwicandelo lamva. ngokunjalo xa isifo sigcwele ngokupheleleyo.
Iinkampani ezahlukeneyo kwihlabathi jikelele bezisebenza kugqatso oluchasene nexesha kwezi nyanga zimbalwa zidlulileyo ukuphuhlisa uvavanyo lokuxilonga olusekwe kwi-NAAT ukuze kufunyanwe i-SARS-CoV-2 esekwe kwiCDC (iZiko loLawulo lweSifo), iAtlanta, USA kunye nezikhokelo ze-WHO ( 1, 2). Abasemagunyeni kwezempilo kwihlabathi jikelele baye bavuma olu vavanyo lokusetyenziswa olungxamisekileyo ukuze kufunyanwe i-SARS-CoV-2. Ufuzo lwentsholongwane egazini ekujoliswe kulo ukuza kuthi ga ngoku lubandakanya ijene ze-N, E, S kunye ne-RdRP, kunye nolawulo olufanelekileyo olulungileyo nolungalunganga. Iisampulu zesigulana eziza kuqokelelwa kuvavanyo olunjalo zisuka kwindawo ephezulu yokuphefumla (i-nasopharyngeal kunye ne-oropharyngeal swab) kunye / okanye indlela yokuphefumula ephantsi (i-sputum kunye / okanye i-endotracheal aspirate okanye i-bronchoalveolar lavage). Nangona kunjalo, kuyenzeka kwakhona ukufumanisa intsholongwane kwezinye iisampuli, kubandakanya isitulo kunye negazi. Iisampulu kufuneka ziqokelelwe ngokukhawuleza ngendlela efanelekileyo zithatha zonke izilumkiso eziyimfuneko kunye nokuthobela iindlela zokhuseleko lwendalo (ngokwemigaqo ebekwe yi-WHO[1]), ukusuka kwizigulana ezidibana nenkcazo yetyala elikrokrelekayo le-COVID-19, ukuyigcina kunye nokupakishwa kwayo. kakuhle ukuba ifuna ukuhanjiswa kwiziko lokuxilonga kwaye iqhutywe (ukukhupha i-RNA kwikhabhinethi ye-biosafety kwi-BSL-2 okanye indawo elinganayo) ngokukhawuleza ngendlela yokuqinisekisa imfezeko yesampulu. Konke oku kufuneka kwenziwe ngokuphambili kulawulo olungcono lweklinikhi kunye nolawulo lokuqhambuka.
Ixesha lokuchongwa kweemvavanyo ezahlukeneyo ezikhoyo ezisekelwe kwi-NAAT eziphuhliswe ziinkampani ezinkulu zokuxilonga kwihlabathi ziyahluka ukusuka kwi-45 min ukuya kwiiyure ze-3.5. Uphuculo oluhlukeneyo lwenziwa kwezi mvavanyo ukuze ziguqulelwe kwiimvavanyo zokunyamekela kwaye zifezekise iziphumo ezinqwenelekayo ngexesha elincinci kangangoko ngaphandle kokuphazamisa ukuchaneka kwesiphumo, ukwandisa inani leemvavanyo ezinokuthi zenziwe ngosuku.
Ezinye iinketho zovavanyo lokuxilonga zi iimvavanyo zokuxilonga ngokukhawuleza (RDTs) ukuba mhlawumbi ibone ii-antigens/iiproteni zentsholongwane ezichazwe kumphezulu we-SARS-CoV-2 amasuntswana entsholongwane njengoko ephindaphindeka kwiiseli ezibambayo kwaye abangele isifo okanye amajoni omzimba ukuphendula usulelo; olu vavanyo lubhaqa ubukho be-antibodies egazini labantu ekukholelwa ukuba bosulelwe yi-COVID-19 (3).
Ukuchaneka kunye nokuveliswa kwakhona kwe-RDT ukufumanisa i-antigens yentsholongwane kuxhomekeke kwizinto ezininzi ezibandakanya ixesha ukusuka ekuqaleni kokugula, ukuxinwa kwentsholongwane kwisampuli, umgangatho kunye nokuqhutyelwa kwesampuli, kunye nokuqulunqwa kwee-reagents ezikhoyo kwiikiti zokuvavanya. Ngenxa yolu tshintsho, ubuntununtunu bezi mvavanyo bunokwahluka ukusuka kuma-34% ukuya kuma-80%. I-drawback enkulu yolu khetho kukuba intsholongwane kufuneka ibe kwinqanaba layo lokuphindaphinda kunye nelosulelo ukuze ibone iiprotheni zentsholongwane.
Ngokukwanjalo, iimvavanyo zokufumanisa ii-antibodies ze-host zisekwe kumandla empendulo ye-antibody exhomekeke kwizinto ezinje ngobudala, imeko yesondlo, ubuzaza besifo, kunye namayeza athile okanye usulelo olucinezela amajoni omzimba. Ingxaki enkulu yolu khetho kukuba ii-antibodies ziveliswa ngaphezulu kweentsuku ukuya kwiiveki emva kokosulelwa yintsholongwane ye-SARS-CoV-2 kwaye umntu kufuneka alinde ixesha elide ukwenza uvavanyo. Oku kuthetha ukuba uxilongo losulelo lwe-COVID-19 olusekwe kwimpendulo ye-antibody iya kuhlala inokwenzeka kuphela kwinqanaba lokubuyisela, xa uninzi lwamathuba ongenelelo lwezonyango okanye othintelo losulelo lwesifo sele edlulile.
Okwangoku, i-RDT ekhankanywe ngasentla ivunyiwe kuphela kwisimo sophando kwaye kungekhona ukuxilongwa kwekliniki ngenxa yokungabikho kwedatha (3, 4). Njengoko ulwazi oluthe kratya lwe-epidemiological lufumaneka kwi-COVID-19, ii-RDT ezininzi ziya kuphuhliswa kwaye zamkelwe njengendawo yovavanyo lokhathalelo kwindawo yeklinikhi njengoko zinokunika iziphumo kwimizuzu eyi-10 ukuya kwengama-30 ngokuchaseneyo novavanyo olusekwe kwi-NAAT oluthathwa ngokomndilili. iiyure ezimbalwa zokubona isifo.
***
Iingxelo:
1. WHO, 2020. Iingcebiso zeSicwangciso soVavanyo lwaseLabhoratri kwi-COVID-19. IsiKhokelo seThutyana. 21 Matshi 2020. Iyafumaneka kwi-intanethi https://apps.who.int/iris/bitstream/handle/10665/331509/WHO-COVID-19-lab_testing-2020.1-eng.pdf Ifikeleleke nge-09 ka-Epreli 2020
2. CDC 2020. Ulwazi kwiilabhoratri. IsiKhokelo seThutyana kwiiLebhu ezifumaneka kwi-intanethi https://www.cdc.gov/coronavirus/2019-nCoV/lab/index.html Ifikeleleke nge-09 ka-Epreli 2020.
3. WHO, 2020. Ingcebiso ngokuSetyenziswa kweeMvavanyo zoNonophelo. Nzululwazi emfutshane. 08 Aprili 2020. Iyafumaneka kwi-intanethi https://www.who.int/news-room/commentaries/detail/advice-on-the-use-of-point-of-care-immunodiagnostic-tests-for-covid-19 Ifikeleleke nge-09 ka-Epreli 2020.
4. ECDC, 2020. Isishwankathelo seMeko yoVavanyo oluKhawulezayo loFundo lwe-COVID-19 kwi-EU/EEA. 01 kuTshazimpuzi 2020. Iziko laseYurophu lothintelo kunye nolawulo lwezifo. Iyafumaneka kwi-intanethi https://www.ecdc.europa.eu/en/publications-data/overview-rapid-test-situation-covid-19-diagnosis-eueea Ifikeleleke nge-09 ka-Epreli 2020
***
